Methods of combating undesired plant growth with substituted carboxamidooxyalkanoic acids and salts thereof

ABSTRACT

UNDSIRED PLANT GROWTH IS COMBATED BY APPLYING TO THE LOCUS OF THE PLANTS A CARBOXYAMIDOOXYALKANOIC ACID HAVING ONE OF THE FOLLOWING STRUCTURAL FORMULAS:   CH3-CO-NH-O-CH2-COOH   CH3-CO-NH-O-CH2-CH2-COOH   (3-CL-PHENYL)-CO-NH-O-CH2-COOH   (3,4-DI(CL-)PHENYL)-CO-NH-O-CH2-COOH   IN ADDITION THERE ARE DISCLOSED THE USE OF OTHER HERBICIDES TO WHICH U.S. PAT. 3,449,113 IS DIRECTED.

United States Patent US. Cl. 71115 1 Claim ABSTRACT OF THE DISCLOSURE Undesired plant growth is combated by applying to the locus of the plants a carboxamidooxyalkanoic acid having one of the following structural formulas:

In addition there are disclosed the use of other herbicides to which US. Pat. 3,449,113 is directed.

SUMMARY OF THE INVENTION This application is a division of Ser. No. 641,487, filed May 26, 1967 and now US. Pat. 3,449,113, which in turn is a continuation-in-part of Ser. No. 374,813, filed June 12, 1964 and now US. Pat. 3,457,063.

The prior application disclosed a variety of types of selectivity among the different compounds, there being no obvious correlation between variations in structural formula and the activity or selectivity in most instances. The present application is directed to use of one class of compositions, the carboxamidooxyalkanoic acids and their water-soluble salts.

Briefly, this invention is the method of combating undesired plant growth which comprises applying to the i locus of the plant a herbicidally effective amount of a compound selected from carboxamidooxyalkanoic acids and their water-soluble salts represented by the general structural formula 3,561,950 Patented Feb. 9, 1971 in which X represents a member of the group consisting of R represents a member of the group consisting of hydrogen and lower alkyl (e.g. methyl) It may vary within the range of zero to two and Y is selected from the group consisting of hydrogen and cations.

DETAILED DESCRIPTION OF THE INVENTION So as to make clear the characteristics of the selective herbicides employed in the method, the procedure and results of controlled comparative tests on a variety of plant species are presented below.

EXPERIMENTAL PROCEDURE FOR HERBICIDE USE A water suspension of the chemical is prepared by combining 0.4 gram of the chemical to be tested with 4 m1. of a solvent mixture (3 parts Emulphor Elf-719 combined with one part xylene and one part kerosene) and then adding sufficient warm water to make ml. of mixture. Emulphor EL-719 is described as a polyoxy- 40 ethylated vegetable oil.

Oats, wheat, peas, radish, flax, millet, alfalfa, tomatoes, and sugar beets are planted in 4 in. pots in the greenhouse. Ten to eighteen days after the emergence of the plants, they are sprayed with the above prepared water emulsions at a rate of 5 pounds of the active chemical per acre and a spray volume of 60 gallons per acre. Seven days after application, the plants are observed and the results of the treatment are as shown in the table.

The plants are rated as follows:

C=Chlorosis (bleaching) N=Necrosis G=Growth inhibition K=Non-emergence F=Formative effect (abnormal form of growth) 0=No effect 1=Slight effect 2=Moderate elfect 3 =Severe effect 4=Maximum eifect or dead plants (In aqueous solution) TABLE-Continued Post-emergent activity at 5 pounds/acre Soy Suger Structural formula of compound Tomato Millet Flax beans Corn Wheat Oats Radish Beets Alfalfa O H Cl( JNOCHzC OrNHn N4 N2, G1 G2 N1, G1 N3, G3 0 0 N1 N4 0 (In (In aqueous solution) 0 H CH3G-N-OCH2OOOH N4 N4 N4 N4 N4 N4 N4 N4 N4 N4 O H CH -OH3-O- JNOCH2C0OH N4 N4 N1 N1 N4 N2 N1 G2 N4 G2 (M.P. 77-79 C.)

O H CICH2CHTO( 7NOOHZCOOH N4 N4 N2, G2 N2, G4 N1 N1, G3 N1 N2, G3 N4 O M.P. 70-7 2) CHg-O-3-N-O-CH2OOOH N4 N4 N3, G3 N4 N4 N4 N4 N4 N4 N4 0 H (M1 85-87") CH K JNOCHZCHZCOOH N4 N4 N4 N3, G4 N4 N3 N3 N4 N4 02, G2

(M.P. 88490 C.)

C H2-C O O H HgC--fil-N-O CHg-COONa N4 F1 N1, G3 N1, G2 0 0 N2 G2 0 O (M.P. 172) H C-O OOH Bil-C-N-O-OHr-OOONa N4 N4 G2 G2 G3 N4 N4 N4 0 C 0 OH GNOCH C O ONa N4 N4 N4 G1 N4 G2 N4 N4 N4 (M.P. over 250) H2 C -C O O H HZG(HJ-NO-OHZ-C O ONa N4 G3 G3 G3 N4 G3 N4 N4 G3 H C O O H H2( 3O H -C-N-OC Hz-C O ONa N4 N4 G3 G2 N1 G1 G2 N4 N4 G2 (M.P. 19l-193) Upon reduction of the rate of application, selective characteristics of the herbicides become more pronounced. Furthermore, some of the specifically exemplified compounds are also elfective as pre-emergent herbicides. This is true of the compound having the structural formula:

-OOOH and its water-soluble salts. This compound is particularly useful in combating weeds in corn. Benzamidooxyacetic acid and its water-soluble salts have been found to possess unusual utility for combating certain weeds in sugar beet fields. The method of accomplishing this specific purpose is the subject of U.S. Ser. No. 543,789 filed Apr. 20, 1966, and now U.S. Pat. 3,396,009 as a continuatiori-irvpart of U.S. Ser. No. 374,813, now U.S. Pat. 3,457,063.

MANUFACTURE OF HERBICIDES PREPARATION OF 3-AMINOOXYPROPIONIC ACID HYDROCHLORIDE A mixture of methyl 3-isopropylideneaminooxypropionate (15.0 g., 0.094 mol derived from acetone oxime and methyl acrylate) concentrated hydrochloric acid ml.), and water (75 ml.) was stirred and heated to boiling. Approximately 25 ml. of distillate was collected then the residual mixture was stripped under reduced pressure 7 and the residue stirred 1 hour with isopropyl alcohol (100 ml.). Filtration and subsequent crystallization from an ethanol-ether mixture gave 7.3 g. (55% M.P. 152-4 C.) of the desired compound.

Analysis.Calculated for C H CINO (percent): C, 25.46; H, 5.68; N, 9.90. Found (percent): C, 25.76; H, 5.49; N, 9.99. I

PREPARATION OF 3-ACETAMIDO- OXYPROPIONIC ACID 3-aminooxypropionic acid hydrochloride (14.1 g., 0.1

8 PREPARATION OF SODIUM N-(3-CARBOXY- PROPIONYL')AMINOOXYACETATE 1 phthalein end-point by the dropwise addition of a solumol), acetic anhydride (15.3 g., 0.15 mol), and glacial acetic acid was stirred, heated, and refluxed 4 hours. The mixture was then cooled and stripped under reduced pres sure on a steam bath. The residual material was then stirred 45 min. with dichloromethane (50 ml.). After filtration and drying there was obtained 5.6 g. (38%, M.P. 88-90" C.) of 3-acetamidooxypropionic acid.

Calculated for C H NO (percent): C, 40.81; H, 6.16; N, 9.52. Found (percent): C, 40.77; H, 6.08; N, 9.53.

PREPARATION OF m-CHLOROBENZAMIDO- OXYACETIC ACID A mixture of m-chlorobenzohydroxamic acid (0.1 mol, 16.5 g.), 'bromoacetic acid (0.1 mol, 13.9 g.), sodium hydroxide (0.2 mol, 8.0 g.), ethanol (150 ml.) and Water (150 ml.) was stirred, heated, and refluxed 5 hours. The mixture was then cooled and acidified with dilute hydrochloric acid. The mixture was then extracted with ethyl acetate (2X 250 ml.) and the extracts were combined and dried over magnesium sulfate. Dilution of the dried extract with n-hexane precipitated the desired product which was removed by filtration and dried. There was obtained 17.1 g. (74%, M.P. 153-5 C.).

Calculated for C H ClNO (percent): C, 47.07; H, 3.51; N, 6.10; Cl, 15.44. Found (percent): C, 47.25; H, 3.86; N, 5.74; C], 15.44.

PREPARATION OF N-(ETHOXYCARBONYL)- AMINOOXYACETIC ACID Bromoacetic acid (0.2 mol) was dissolved in water (50 ml.) and neutralized to a phenophthalein end-point with 10% sodium hydroxide. N-hydroxyurethane (0.2 mol) was added, followed by the addition of 10% sodium hydroxide (0.2 mol). The mixture was stirred 2 hours at room temperature, then concentrated to 50 ml. volume under reduced pressure. The concentrate was acidified with dilute HCl and extracted with ethyl acetate (3X 75 ml.). The extract was dried over magnesium sulfate and the solvent removed under reduced pressure. The residue was stirred with benzene (250 ml.) until crystalline, filtered, washed with hexane and dried. There was obtained 16.0. g. of product (M.P. 77-9" C.).

Analysis.Calculated for C H NO (percent): C, 36.81; H, 5.56; N, 8.58. Found (percent): C, 36.49; H, 5.48; N, 8.13.

PREPARATION OF N-(METHOXYCARBONYL) AMINOOXYACETIC ACID Aminooxyacetic acid hemi-hydrochloride (11.99 g., 0.11 eq.), acetic acid (50 ml.) and methyl chloroformate (9.4 g., 0.1 mol) were stirred, heated and refluxed 3 hours. The mixture was cooled and volatile material removed under reduced pressure. The residue was extracted with hot ethyl acetate (80 ml.) and the extract diluted with hexane (400 ml.) and stirred overnight. The product was removed by filtration and dried giving 8.7 g. (M.P. 8587 C.).

Analysis.Calcu1ated for C H NO (percent): C, 32.22; H, 4.73; N, 9.39. Found (percent): C, 32.35; H, 4.82; N, 9.21.

tion of sodium methoxide in methanol. The neutralized mixture was stirred 30 min., then filtered to remove sodium chloride. The filtrate was added to a solution of succinic anhydride (0.1 mol) in methanol (300 ml.). This mixture was stirred 30 minutes and the product removed by filtration, washed with methanol ml.) and dried. There was obtained 16.1 g. (M.P. 178-80 C.) of the desired product.

Analysis.Calculated for C H NaNO (percent): C, 33.81; H, 3.78; N, 6.57; Na, 10.79. Found (percent): C, 33.75; H, 3.99; N, 6.20; Na, 10.66.

In controlling plant growth by means of herbicides it is necessary to obtain penetration of the formulation through waxy protective layers to obtain contact with plant fluids, and once contact is obtained, water solubility is desirable so as to cause the systemic migration of the herbicide. Water solubility and ability to penetrate or dissolve waxy cuticle are characteristics which seldom appear in a single substance and, in most instances, are not possessed by the herbicides themselves. It is therefore necessary to employ organic solvents in combination with solubilizers, dispersants, emulsifiers or other surface active agents in herbicide formulations. Furthermore, when using highly active herbicides, it is difficult to obtain uniform distribution of a small quantity of material unless it is dispersed or dissolved in a larger quantity of diluent before application. Preferred diluents are water and inert solids. From a practical standpoint, water is the preferred diluent because it is cheap and spray application is more convenient than dusting. The preferred formulations for use in the present method are water-dispersible solutions of herbicides in organic solvents or dispersible powders. The herbicides themselves are soluble in water in the form of water-soluble salts, so they may be sold and transported as concentrated aqueous solutions. In warm climates where there is no danger of freezing and breaking containers, aqueous solutions may be preferred, especially solutions of sodium or ammonium salts.

What is claimed is:

1. The method of combating undesired plant growth which comprises applying to the locus of the plant a herbicidally effective quantity of a compound of the formula References Cited UNITED STATES PATENTS 3,162,525 12/1964 Leasure 71113 3,282,987 12/1966 Ellis 260-471 3,396,009 8/1968 Neighbors 71115 3,420,824 1/ 1969 Ellis 260244 3,449,113 6/1969 Neighbors 71106 3,457,063 7/1969 Neighbors 711 15 LEWIS GOTI S, Primary Examiner M. M. KASSENOFF, Assistant Examiner U.S. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 34561 .950 Dated February 9 1971 Ralph P. Neighbors Inventor(s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In the heading to the printed specification, lines 5 to 7 "Gulf Research 6 Development Company, Pittsburgh, Pa. a corporation of Delaware" should read Gulf Oil Corporatic Pittsburgh, Pa. a corporation of Pennsylvania Signed and sealed this 2nd day of November 1971 (SEAL) Attest:

EDWARD M. FLETCHER,JR ROBERT GOTTSCHALK Attesting Officer Acting Commissioner of Pate] 

